Integer Constants
Description
Integer constants are numbers that are used directly in a sketch, like 123. By default, these numbers are treated as int but you can change this with the U and L modifiers (see below).
Normally, integer constants are treated as base 10 (decimal) integers, but special notation (formatters) may be used to enter numbers in other bases.
| Base | Example | Formatter | Comment |
|---|---|---|---|
| 10 (decimal) | 123 | none | |
| 2 (binary) | B1111011 | leading 'B' | only works with 8 bit values (0 to 255) characters 0&1 valid |
| 8 (octal) | 0173 | leading "0" | characters 0-7 valid |
| 16 (hexadecimal) | 0x7B | leading "0x" | characters 0-9, A-F, a-f valid |
Decimal (base 10)
This is the common-sense math with which you are acquainted. Constants without other prefixes are assumed to be in decimal format.
Example Code:
Binary (base 2)
Only the characters 0 and 1 are valid.
Example Code:
The binary formatter only works on bytes (8 bits) between 0 (B0) and 255 (B11111111). If it is convenient to input an int (16 bits) in binary form you can do it a two-step procedure such as:
Octal (base 8)
Only the characters 0 through 7 are valid. Octal values are indicated by the prefix "0" (zero).
Example Code:
It is possible to generate a hard-to-find bug by (unintentionally) including a leading zero before a constant and having the compiler unintentionally interpret your constant as octal.
Hexadecimal (base 16)
Valid characters are 0 through 9 and letters A through F; A has the value 10, B is 11, up to F, which is 15. Hex values are indicated by the prefix "0x". Note that A-F may be upper (A-F) or lower case (a-f).
Example Code:
※ NOTES AND WARNINGS:
U & L formatters:
By default, an integer constant is treated as an int with the attendant limitations in values. To specify an integer constant with another data type, follow it with:
- A 'u' or 'U' to force the constant into an unsigned data format. Example: 33u
- A 'l' or 'L' to force the constant into a long data format. Example: 100000L
- A 'ul' or 'UL' to force the constant into an unsigned long constant. Example: 32767ul
See Also
- Language : constants
- Language : Floating Point Constants
※ ARDUINO BUY RECOMMENDATION
| Arduino UNO R3 | |
| Arduino Starter Kit |